 (Bi) Kini

Aloha

One of the most usable of the pleasant, newly adopted nature/water names (like Lake and Ocean), especially in middle position. 
 There was a character named Bay Kennish on the show Switched at Birth; conservative political commentator Bay Buchanan was born Angela Marie.
 Other associations with bay are the bay laurel tree, prized since ancient times for its medicinal and culinary (bay leaves!) properties, and the reddish-brown color usually applied to horses.

With the tide coming in on a new wave of word names, this one just might catch on, especially for parents who relish sun, sand, and surf. Forest lovers can spell it Beech, like the tree. 

Beach

Barnacle

Bluff

Bubbles

Carver is an occupational name with an artistic bent, as is the newly arrived Painter, which has a fresher feel than the 1990's Carter. It also has eminent last-name links to botanist and educator George Washington Carver and short story master Raymond Carver. 
 Carver appears as a character in the R. D. Blackmore classic Lorna Doone.

Carver

Cove is an up-and-coming nature name whose cool sound and peaceful image saw it rising for both sexes... until COVID-19 hit. It remained steady in use for boys in 2021, but actually increased for girls, although it remains a seriously rare and distinctive choice for either gender. 

Cove

Cabana/Cabanna

Choppy

Copper(tone)

Coral/Koral

Crest

Dune is a name of several layers. It's a modern nature name, like Ocean, Bay and Reef, although rarer, conjuring up images of breezy sand dunes on summer beach days.
 
It's also assocated with Frank Herbert's Dune iconic series of sci-fi novels. The name increased in popularity in 2021, when the most recent movie adaptation was released.

Dune

Dawn

Digger

Drifter

Most parents today call their Edwards Edward -- and we tend to think that's the right call. But it's worth noting that Eddie has been in the Top 1000 every year since records began in 1880; indeed, it was a mainstay on the Top 100 through the 1950s.

Eddie

Suggests the salty, windswept air of the seashore. 

Gull

Kayak

Kelp

Pearl, like Ruby, has begun to be polished up for a new generation of fashionable children after a century of jewelry box storage. The birthstone for the month of June, Pearl could also make a fresher middle name alternative to the overused Rose. Cool couple Maya Rudolph and Paul Thomas Anderson named their daughter Pearl Minnie, followed by Jack Osbourne, and several celebs have put it in the middle spot, as in Busy Philipps's Cricket Pearl, Jake Owen's Olive Pearl and Caleb Followill's Dixie Pearl .
After being a Top 25 name in the late nineteenth century, Pearl went into a long slide, but is showing signs of a strong comeback -- it reentered the Top 1000 in 2010.
 In Nathaniel Hawthorne's The Scarlet Letter, Pearl is the illegitimate daughter of Hester Prynne, who gives her the name because she is 'her mother's only treasure.'
 Pearl was also the alter ego name of Janis Joplin, tied to singer Pearl Bailey, and---hmm--the birth name of western writer Zane Gray.
 Variations are PERLE and PERLA.

Pearl

Pebbles

Modern surfer boy. Just don't call him Reefer. 

Reef

How many decades will it take for Rocky to triumph over its association with Sylvester Stallone's battered but not beaten boxer? The moment may have come, now that Sarah Michelle Gellar and Freddie Prinze Jr. have named their son Rocky. It helps, too, that Madonna's son Rocco helped make the name child-appropriate again.

Rocky

A sweet Scottish short form of Alexander which is feeling newly appealing now the era of Sandra is far behind us. Sandy would also work well as a nickname for a child with pale red or dark blond hair.

Sandy

Shelly

Upbeat nickname-name that can't help but make you smile, along with its soundalike Sonny. Sunny Pawar, the five-year-old star of the 2016 smash-hit movie Lion, was cast from among thousands of young hopefuls after auditioning at his school in Mumbai. Sunny is often heard in India as a nickname for Sunil, Sundeep or Sunita, but it’s also bestowed as a standalone with the literal meaning of "sunny; radiant; cheerful".

Sunny

Shoal

Shredder

Splash

Stormy

Surfer

Swell

As likely to be tied to the detergent as to the rhythms of the ocean. 

Tide

Wave

liney143's list "Beach related names" of 38 great name ideas:  (Bi) Kini - Wave!

Beach related names

Names that could be used for pets or people.